In general, a blade bending apparatus is an apparatus for continuously bending a strip-shaped blade, which is wound around a roll, by using a bending pin. In order to continuously bend the strip-shaped blade in the blade bending apparatus, it is important to transfer the blade from the roll at an adequate rate. When the strip-shaped blade has a straight shape, the blade is put on a horizontal rotating roller and transferred by a frictional force between a surface of the blade and the roller.
However, in case of an arc type blade 10 illustrated in FIG. 1, because an inner radius r and an outer radius R of the blade are different from each other, it is needed to make the transfer of the inner radius portion and the transfer of the outer radius portion different so as to maintain the shape of the arc type blade as it is. Because the horizontal roller used for transferring the conventional straight type blade has a constant diameter over the whole circumferential surface, the horizontal roller is not useful for transferring the arc type blade which should be transferred under the condition that the transfer of the inner radius portion is different from the transfer of the outer radius portion.
An arc type blade transfer apparatus of a prior art is disclosed in Japanese Patent Laid-open Publication No. 8-332524. As shown in FIG. 2, an arc type blade transfer apparatus of the prior art comprises pressure rollers 700 and 701 for pressurizing the outer peripheral surface of the arc type blade 10, and a driving gear 720 for transferring the arc type blade 10 by being tooth-engaged with slits 11 formed at the inner peripheral surface of the blade 10. Another arc type blade transfer apparatus of a prior art is disclosed in Korean Patent Laid-open Publication No. 10-2003-0025677. As shown in FIG. 3, an arc type blade transfer apparatus of the prior art comprises a transfer unit 800 which holds the arc type blade 10 and is rotated around a center point O.
However, because the prior art transfer apparatus illustrated in FIG. 2 uses the slits 11 formed at the inner peripheral surface of the arc type blade, when a shape of the slits 11 or a gap between the slits 11 is changed, the driving gear 720 should be replaced correspondingly to the changed slits. Also, because the prior art transfer apparatus illustrated in FIG. 3 requires devices for supporting the arc type blade and rotating the transfer unit 800 around the center point, a structure becomes complicated.